Alright guys, I'm about done with this Impala. It's my wife's mail car, and is currently sitting at 160k miles.

Here's the problem:
She was finishing her route when she had to stop and deliver a package, turned off car, came back and wouldn't start. We could give it gas and it would start, and keep running as long as the gas pedal was pressed, however, once the gas was released the car would die. She's had an ongoing issue of this car dying, ESPECIALLY, if coming to a red light/stop. If you pull over, the car will start right up.

When I got it home, I turned the car off, and waited about 10-20 minutes, and I couldn't get it to crank without pressing the gas. I opened the hood, and the only visible thing I could see was a loose belt tensioner, but that wouldn't cause this problem, and I don't have a battery light on. After another hour or 2, and the engine has cooled down. The car fires right up without any problem.

So, what do you think? I'm leaning toward the 24x Crankshaft sensor. I've checked the FPR, and it's not leaking, within last 6 months cleaned the TB and the MAF. I had a misfire code about 3 months ago also, noticed one of the plug wires was cut, and replaced all of them. Apparently, gas got down into the cat though and ruined it, so I had to replace it also.

Before I even finished, I was thinking crankshaft position sensor when you mentioned the ongoing stalling problem. I don't know if that is related to the "gas" pedal issue or not, but I might start there (CPS).

I've got the car in a shop now, and he's had it for 3 days, can't reproduce it, and checks out fine on his computer. He's going to charge $120 to change the crank sensor for me, and I guess I'll see how it goes after that.

When you say it won't even crank without pressing the gas, do you really mean the engine won't turn without pressing the accelerator? Cause that makes no sense at all... I can't think of a thing that would cause that. Now if you mean that it won't fire without pressing the gas, that opens up the possibilities. Still lean towards the CPS, if you're already doing it, let us know how it turns out.

Well, it didn't fix my problem. Wife finished her route, came home, let the car sit for an hour or so, and took it out to get the kids. Within about 5 miles, when pulling up to a red light, the car dies. She tried to crank it for a little while, and it wouldn't start without giving it gas. So she sat, without trying to crank for 10 minutes and let the engine cool a bit, and it fired right up.

No idea on the relearn, my wife is out on her route today. If there's still a problem, I'll make sure to ask the mechanic who changed it. Anyone got a working Tech II they want to give away for free? :-)

ICM didn't fix the problem. I asked the guy who replaced the Crank sensor if he did a Crank Angle Sensor Error (CASE) relearn, and he had no idea what I was talking about or that he'd ever had to do it before. I asked if he had a tech II, and we could do it. He said yah, and went and grabbed an OBD II. I let him figure out that thing wouldn't do it. He's going to call the dealership and find out what that is, and give me a call back.

Sigh...I can't blame the mechanic honestly. He's a super nice guy, and he's not charging me for the stuff that doesn't fix it.